If the fetus suddenly moves abnormally frequently in the uterine cavity or the fetal movement decreases significantly, it is considered that the fetus has signs of intrauterine hypoxia, and it is recommended to go to the hospital for examination in time. If the fetal heart rate is greater than 160 beats/min or less than 120 beats/min, it can also be determined that the fetus is suffering from intrauterine hypoxia. The presence of intrauterine hypoxia can also be determined by measuring the umbilical cord blood flow resistance index during ultrasound.